POWER SKIDDL\G 223 
triangle being attached to the under side of the cable and the 
support being attached to the side of the triangle next to the spar. 
When the trolley reaches the intermediate support, the lower 
sheave follows along the side of the triangle to the apex and in so 
doing widens the distance between the upper and lower sheave 
so that the trolley will pass the hanger. As soon as the latter is 
passed the two sheaves come together and close the gap. Since 
the trolley is longer than the cable support on the intennediate 
spar, both top sheaves are not on the support at one time and, 
therefore, it is impossible for the trolley to leave the cable. 
The crew for operating a cableway skidder with a slack pulling 
device consists of 13 or 14 men, as follows: 
1 skidder leverman 1 head rigger 
1 fireman 2 rigging helpers 
1 tong hooker 1 tong unhooker 
1 or 2 helpers 1 run cutter 
1 signal man 1 loading leverman 
1 top loader 1 ground loader 
The daily output of the Lidgerwood type of skidder in the 
cypress region is from 35,000 to 40,000 feet, in the Northwest 
from 50,000 to 80,000 feet, in the mountains of West Virginia 
on long spans from 30,000 to 35,000 feet, and when used as a 
relay system from 25,000 to 30,000 board feet. These figures 
are averages only, since the output is influenced to a marked 
degree by the size and density of timber, the length of span, and 
the topography of the country'. 
MacFarlane System} — This was developed in the West pri- 
marily for logging steep slopes, up or down which logs could not 
be successfully taken by the ground methods in general use. 
It has been used successfully for yarding when the span was 2500 
feet. It is also now used for logging in rolling countrj^ and to 
move logs from the ground and high-lead yarders to the railroad, 
a process known as " swinging. "^ 
This system uses a Ij- to l|-inch main cable which passes 
from a drum on the engine up to and through a block in the head 
spar, thence to and through a block on the tail spar tree, the end 
^ See Logging in the Douglas Fir Region, by W. H. Gibbons. U. S. Dept. 
of Agriculture, Bui. No. 711, and The Timbermaq, April, 1911, p. 49, and 
May 1912, p. 27. 
* See page 245. 
